Rectilinear Steiner Trees with Minimum Elmore Delay

We provide a new theoretical framework for constructing Steiner routing trees with minimum Elmore delay. Earlier work [3, 13] has established Elmore delay as a high delity estimate of \physical", i.e., SPICEcomputed, signal delay. Previously, however, it was not known how to construct an Elmore delay-optimal Steiner tree. Our main theoretical result is a generalization of Hanan's theorem [11] which limited the number of possible locations of Steiner nodes in an optimal delay rectilinear Steiner tree. Another theoretical result establishes a new decomposition theorem for constructing optimal-delay Steiner trees. We develop a branch-andbound method, called BB-SORT-C, which exactly minimizes any linear combination of Elmore sink delays; BB-SORT-C is practical for routing small nets and for delimiting the space of achievable routing solutions with respect to Elmore delay.

• Type: Conference
• Year: 1994
• Where: DAC
• Authors: Kenneth D. Boese, Andrew B. Kahng, Bernard A. McCoy, Gabriel Robins
• Keywords: Computer Architecture, DAC 1994, Elmore Delay, Minimum Elmore Delay, Steiner Trees